1. Field of the Invention
The present invention relates, in general, to electromagnetic actuating devices and, specifically, to linear positioning devices utilizing electromagnetic actuating means to control the incremental advance of a movable member.
2. Description of the Prior Art
Electromagnetic actuating devices have been employed to incrementally advance a magnetic member upon repeated energization of the device. Such devices utilize an electrical coil and a magnetic core including at least one movable core member which is attracted to another portion of the core by the magnetic flux induced in the core when electric current is applied to the coil.
Numerous configurations for electromagnetic actuating devices have been devised for different applications and some include a plurality of coils and movable cores for variable, discrete advance of a movable core depending upon the magnitude of the current applied to the coils or the number of coils which are energized. Other incremental positioning devices simply operate in an on/off mode, that is, the movable member moves to one position when the coil is energized and then returns to the start position when current is removed from the electric coil.
Spring biasing means have also been employed to reset the movable core in its start position spaced from the other core portion when the electric current is removed from the coil. Pawl and latch devices have also been employed in such linear actuators to hold the movable member in a stationary advanced position after power has been removed from the coil.
It would be desirable to provide a novel linear motor for incrementally advancing a movable member or workpiece in a stepwise fashion upon repeated energization of the motor. It would also be desirable to provide a linear motor which has a simple construction and can be adapted for use in many different applications.